神经网络PID算法在漆包线检测仪中的应用

为检测漆包线的热性能，设计了温度控制系统。利用BP神经网络在线修正PID参数，从而获取最优的一组参数，并将BP-PID控制算法应用于该温控系统。利用MATLAB进行仿真试验，验证了该控制系统能达到较好的控制效果。利用漆包线检测仪进行实物试验，结果表明：当控制温度为120 ℃时，该控制方式与传统PID控制相比具有更好的控温效果，超调率小于4%、稳态精度小于 2 ℃，达到了预期目的     

基于模糊变系数PID算法的注塑机料筒温度控制

注塑机料筒温度是注塑工艺的重要参数,对料筒温度进行有效地控制是保证塑料制品成型质量的重要环节.料筒温度系统是一个多变量、离散、间歇工作、大滞后、非线性、强耦合且需要人工参与的复杂系统.本文采用模糊变系数PID控制,用模糊规则对模糊变系数PID算法中的系数进行在线修正.结果表明该算法提高了温度控制系统的鲁棒性,超调减小,...     

中频感应电炉温度补偿控制系统研究与分析

中频感应电炉温度控制存在严重的滞后现象,传统的PID温度控制出现超调量较大、温度调整周期过长等问题。采用改进型史密斯补偿控制系统后,克服纯滞后时间对控制系统的影响。通过MATLAB对控制系统进行仿真,发现温度控制变得更加精确、平稳,缩短系统调整至稳态所需时间,控制过程中的超调量明显降低。系统的整体抗干扰性和鲁棒性得到进一步提高,满足了生产中对中频感应电炉温度控制各项参数指标的要求。     

C32摩擦焊机的神经网络PID自适应控制研究北大核心

针对C32连续摩擦焊机闭环控制系统的时变性、非线性控制精度较低以及稳定性较差等问题,研究一种BP神经网络与增量式PID控制器相结合的控制算法来提高系统性能。参考C32连续摩擦焊机实际运行参数,通过AMESim软件建立物理模型;结合Simulink建立神经网络PID自适应控制器进行联合仿真,建立电液力闭环控制系统。结果表明:C32摩擦焊机非线性控制系统在神经网络PID自适应控制下的响应速度、上升时间、控制精度以及稳定性皆优于传统PID控制;BP-PID在非线性控制中快速响应的同时消除了原有控制器的超调量,极大地提高了系统稳定性。     

基于AMESim与Simulink的变柔性负载实验台变频式电液控制系统建模与仿真研究

在建立变柔性负载实验台变频式电液力控制系统的数学模型的基础上,利用AMESim和Simulink建立系统仿真模型,并进行基于PID控制和模糊自适应PID控制的联合仿真.仿真结果表明:基于模糊自适应PID算法的变频式电液力控制系统改善了系统的响应,减小了超调量,可应用于工程实际.     

主动防翻装置控制系统设计

针对主动防翻装置液压回路和控制参量特点,设计了基于模糊PID算法的液压控制系统。并应用Simulink对常规PID算法和模糊PID算法进行仿真,通过对比发现采用模糊PID算法时,控制系统的调节时间缩短了0．025s、最大超调量减小了17．9％,表明模糊PID控制算法在此系统中具有更好的适应性,满足主动防翻装置的整体性能要求,为进一步控制系统的硬件设计提供了依据。     

采煤机滚筒调高智能化控制系统优化设计

为提高采煤机滚筒调高智能化控制精度,对基本萤火虫算法进行改进。对采煤机滚筒调高智能化控制系统进行数学建模,利用改进的萤火虫算法进行滚筒控制系统PID参数寻优,并搭建滚筒调高智能化控制系统Simulink仿真模型;对采用改进和基本萤火虫算法系统的响应进行分析。结果表明：系统在阶跃信号、斜坡信号及不同类型干扰信号情况下,改进萤火虫算法优化的PID控制器的系统响应性能和抗干扰性能均得到明显改善;阶跃信号下,优化后系统的超调量减小21.6%;斜坡信号下,优化后系统超调量减小38.4%;脉冲干扰信号下,优化后系统超调量减小21.9%;阶跃干扰信号下,优化后系统超调量减小33.2%;随机干扰信号下,优化后的响应曲线波荡范围减小40.1%。     

超磁致伸缩执行器串级温度控制策略研究

为减少温度对超磁致伸缩执行器(GMA)输出位移的影响,采用串级PID控制策略对GMA进行精确温度全闭环控制.通过热平衡方程推导了GMA的传热学数学模型,并建立了串级PID控制策略的实施方案.采用遗传算法对串级PID控制器进行PID参数优化整定.仿真结果表明,遗传算法优化得到的GMM温度阶跃响应曲线的调节时间和超调量指标均优于单纯形法优化后的响应曲线指标.而在GMA温控平台上的试验结果表明,串级PID控制获得的GMM温度阶跃响应调节时间513.2s,超调量2.75％,温控精度可达±0.1℃,控制效果远远优于单环控制.     

专家控制器在阳极焙烧温度控制中的研究

在阳极焙烧温度自动控制系统中,采用PLC内部的PID进行温度控制时会出现超调、振荡等现象.为满足阳极焙烧温度的控制精度及系统跟踪控制要求,提出一种基于专家系统的PID混合控制策略.用该方法设计了专家PID温度控制器并进行实验,实验结果表明该控制器弥补了传统PID不足,且具有设计简单、较易实现、提高温度控制的精度和速度等特点.     

冷连轧机张力系统模糊PID控制仿真研究

运用电机电气控制系统,结合冷连轧塑性变形原理,对带钢冷连轧机系统建立了稳态的数学模型。并用MATLAB /Simulink对冷连轧动态过程进行了数值模拟仿真。针对冷连轧控制系统中存在时滞、时变、大惯性、非线性等问题和传统PID控制器整定参数的局限性,提出了将模糊控制和传统PID控制结合在一起,构造成一个模糊PID控制器。最后通过数值模拟仿真实验证明：与传统PID控制器相比,模糊自适应PID控制器的动静态性能好,即响应时间短,超调量小,稳态性能好。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.     

Microstructures and Mechanical Properties of a Newly Developed Austenitic Heat Resistant Steel

The effect of heat treatment on the microstructures and mechanical properties of a newly developed austenitic heat resistant steel(named as T8 alloy) for ultra-supercritical applications have been studied. Results show that the main phases in the alloy after solution treatment are γ and primary MX. Subsequent aging treatment causes the precipitation of M_(23)C_6 carbides along the grain boundaries and a small number of nanoscale MX inside the grains. In addition, with increasing the aging temperature and time, the morphology of M_(23)C_6 carbides changes from semi-continuous chain to continuous network.Compared with a commercial HR3C alloy, T8 alloy has comparable tensile strength, but higher stress rupture strength. The dominant cracking mechanism of the alloy during tensile test at room temperature is transgranular, while at high temperature, intergranular cracking becomes the main cracking mode, which may be caused by the precipitation of continuous M_(23)C_6 carbides along the grain boundaries. Typical intergranular cracking is the dominant cracking mode of the alloy at all stress rupture tests.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

The 15th Global Foundry Sourcing Conference 2014held in Qingdao China

Organized by Suppliers China Co., Ltd and co-organized by the National Technical Committee 54 on Foundry of Standardization Administration of China, the 15th Global Foundry Sourcing Conference 2014 （hereinafter referred to as FSC 2014） was successfully held on Sep. 23rd in Grand Regency Hotel, Qingdao. More than 500 delegates from home and abroad attended this conference, including over 130 purchasers from 20 countries and 380 domestic and foreign suppliers.     

Secondary Recrystallization Behaviors of Grain-Oriented 6.5 wt% Silicon Steel Sheets Produced by Rolling and Nitriding Processes

By rolling and nitriding processes, 0.23- to 0.3-mm-thick grain-oriented 6.5 wt% silicon steel sheets were produced. The core losses of grain-oriented 6.5 wt% silicon steel at frequencies ranging from 400 Hz to 20 k Hz were lower than that of the grain-oriented 3 wt% silicon steel with the same thickness by 16.6–35.8%. The secondary recrystallization behavior was investigated by scanning electron microscopy, energy-dispersive spectroscopy, and electron backscattered diffraction. The results show that the secondary recrystallization in high-silicon steel sheets develops more completely as the nitrogen content increases after nitriding, secondary recrystallized grain sizes become larger, and the sharpness of Goss texture increases. Because more {110}116 grains in the subsurface and the central layer of the sheets have a lot of 20°–45° high-energy boundaries in addition to Goss grains, {110}116 can be the main component through selective growth during secondary recrystallization when the inhibitor quantity is not enough and inhibitor intensity is weaker. The increases in nitrogen content can increase the inhibitor intensity and hinder abnormal growth of a mount of {110}116 grains and therefore enhance the sharpness of Goss texture.     

Laser Cladded TiCN Coatings on the Surface of Titanium

Laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs (OM). The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm / s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm - 2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2, and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80?滋m, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

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正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis